In conventional anodizing technology, series 5 and series 6 aluminum alloys are usually anodized for protecting a surface of aluminum material thereof. However, due to compositions of the series 5 and series 6 aluminum alloys, the series 5 and series 6 aluminum alloys have a relatively low material strength and there are many restrictions on structural designs thereof. The high strength aluminum alloy of series 7 has a high strength. However, in conventional technology, other surface treatments, such as an electrophoresis, etc. are generally used on the series 7 high strength aluminum alloy. If the anodization is performed on the series 7 high strength aluminum alloy, a material texture is easily formed on a surface of the series 7 high strength aluminum alloy whereby a surficial brightness capability thereof is not good enough.